Maxmind country lookup

Existing solutions

There are a few but they use the city/block tables and also seem to be mysql specific. As I don't want to try converting a bunch of Polygon code to postgres format I thought I'd just convert the fairly simple django geoip-redirect code.

• rack-geoip
• geoip-rails

Database setup

Grab the country csv.

wget -O /tmp/csvdb.zip http://geolite.maxmind.com/download/geoip/database/GeoIPCountryCSV.zip;
unzip csvdb.zip;

SQL for tables:

CREATE TABLE geoip_country (
    id SERIAL PRIMARY KEY,
    start_ip char(15) NOT NULL,
    end_ip char(15) NOT NULL,
    start_decimal bigint NOT NULL,
    end_decimal bigint NOT NULL,
    country_code varchar(2) NOT NULL,
    country_name varchar(120) NOT NULL
);

COPY geoip_country
    (start_ip, end_ip, start_decimal, end_decimal, country_code, country_name)
    FROM '/tmp/GeoIPCountryWhois.csv' DELIMITERS ',' CSV;

I should probably rake task all that!

Usage

In your application controller you can set it to fire as a filter using:

before_filter :geoip

And then adding to your controller:

def geoip
    # Lookup the current request IP and assign to session vars, if we've looked
    # it up before then skip further requests and return the session version
    if session[:country_code].nil?
      @country_code = Geoip::Country.find_by_ip(request.remote_ip)
      session[:country_code] = @country_code
    else
      @country_code = session[:country_code]
    end
    return @country_code
end

This will cache the first lookup to the users session; which is probably how you'll want to use it for most cases. To use elsewhere expose the method as a helper in your controller:

helper_method :geoip

Heroku

Simply push your loaded country table to heroku.

heroku db:push --tables geoip_country